Cellulosic textile finishing



United States Patent 3,206,273 CELLULOSIC TEXTILE FINISHING FritzMunzel, Wattwil, Sanirt Gallen, Switzerland, as-

signor, by mesne assignments, to Heberlein & (10., A.G., Wattwil,Switzerland, a corporation of Switzerland No Drawing. Filed .luiy 19,1961, Ser. No. 125,689 Claims priority, application Switzerland, July22, 1960, 8,398/60 8 Claims. (Cl. 8116) This invention relates to animproved method of finishing cellulosic textile materials to improvecertain physical properties thereof, particularly the crease resistance,ten

textile, and to the novel product thereby produced.

- not required.

sile or tearing strength, and the abrasive strength of the It is relatedto Heberlein et al. US. application No. 62,068, filed March 31, 1960,and constitutes an improvement over the method therein described.

The term cellulosic textile material as employed herein is intended toinclude films, yarns, fibers, filaments or threads as such or in theform of cast sheets, woven, knit, felted or non-woven fabrics,consisting of natural or re generated cellulose, as well as such fibers,fabrics, etc, which are made up of a major portion of cellulose orregenerated cellulose, but which also contain in addition a smallquantity of non-cellulosic material.

It is Well known that in order to improve the crease resistance ofnatural or regenerated cellulose yarns or fabrics, for example, cotton,rayon, or mixed cotton and rayon goods, the yarn or fabric isimpregnated with one or more well-known condensable resin-formingsubstances, for example a synthetic resin precondensate dispersed ordissolved in a fluid carrier containing a condensation catalyst which isusually acidic. Following impregnation the excess resin precondensate issqueezed out and the impregnataed fabric is then subjected totemperatures well above 100 C. for a time snificient to cure the resin.Textiles finished in this conventional manner at elevated temperatureare substantially less durable than the unfinished or starting material.While conventional finishing imparts improvedcrease' resistance, this isaccomplished at the expense of a marked reduction in fiber strength ofthe textile product, as evidenced either by appreciably reduced tensileor tearing strength or resistance to abrasion or both.

According to related Heberlein et a1. U.S. application Serial No.62,068, a method is suggested whereby the cellulosic textile to befinished is first treated .with a condensable or resin-forming substanceand subsequently subjected to ionizing radiation, more particularly toelectromagnetic ionizing radiation, which facilitates condensation andcuring of the resin-forming substance on the textile. The method thereofmay be carried out with or without the usual condensation catalyst, butheat is The product produced by the related methodexhibits'substantially improved crease resistance as compared with thisproperty of the same conventionally finished textile. Tearing strengthof the textile finished in accordance with the related application is insome instances, although not always, improved. Occasionally tearingstrength is slightly reduced.

While it is generally agreed that a finish superior to that of theconventional method can be imparted to the textile by the method of theearlier related application, there is still a need for a method whichwill assure superior crease resistance results accompanied by improvedtearing and abrasive strength, without degradation of the cellulose.

I have found that these results can be obtained by following the generalprocedures outlined in the related application as respects applicationof the condensable or resin-forming substance, but instead of subjectingthe thus treated textile to electromagnetic ionizing radiation,

3,Z5,Z73 Patented Sept. 14, 1965 the impregnated material is irradiatedwith accelerated electrons of a critical low particle energy to acritical total dose.

It has already been proposed to employ accelerated electrons (betaradiation) to effect condensation of synthetic resins on cellulosictextiles, but the methods previously described have always employed veryhigh energy beta particles. More particularly, the prior art techniquesemploy beta radiation of a particle energy of 2 mev. and higher, withthe total doses irradiated being between about 5X10 and 7x10 rad. Theseprior art techniques have been acknowledge to be'insufiicient for theproper finishing of cellulosic textile materials in that they cause veryextensive degradation of the cellulosic substrate thus rendering itsfurther use as a fabric impossible. Furthermore, at these high energylevels satisfactory resin condensation is not achieved and an acceptablefinish is thus not imparted to the fabric.

It has been established that extensive decomposition of cellulose andregenerated cellulose occurs when it is subjected to total doses ofionizing radiation above 25x10 rad. For example, at total doses of 5 l0rad at least 10% of the cellulose is converted to sugars. Furthermore,many of the resin precondensates usually employed for the finishing ofcellulosic textiles such as urea, melamine and ethyleneurea, are alsosensitive to radiation and are extensively decomposed at total doses ofmore than 2.5 X 10 rad. Accordingly, the unsatisfactory resultsattending the aforementioned prior art attempts at finishing with theuse of high energy beta particles is not surprising.

in accordance wtih the method of the present invention excellent resincondensation on the cellulosic material can be achieved without anysignificant degradation of the cellulose or the resin precondensate ifthe textile materials are subjected to the action of acceleratedelectrons of a critical particle energy of less than 1 mev., and if atotal dose imparted is less than 2x10 rad. The present processcontemplates the use of accelerated electrons of a particle energybetween about 0.05 and 1 mev., and preferably between 0.05 and 0.6 mev.,with irradiation being to a total dose above 10 but below 2x10 rad,preferably between 10 and 10 rad.

The excellent results obtained by the method of the present inventionmentioned above and set forth in detail hereinafter are indeedsurprising, since one skilled in the art would not expect that theirradiation of resin precondensate impregnated cellulosic textiles withaccelerated electrons of such a low particle energy and at acomparatively low total dose would produce sufiicient resin condensationto effect the desired crease resistance and dimensional stabilityimprovement. From the teachings of the prior art, one would assume thatsufficient resin condensation or linking of the resin to the cellulosicmolecule could not be achieved with accelerated electrons since at muchhigher doses and particle energies poor condensation is achieved anddegradation of the cellulosic substrate is appreciable.

It is believed that the success of the method of the present inventionis due to the fact that electromagnetic ionizing radiation (gamma rays)pass through the irradiated material on the shortest possible path, withat most only about 1% of their energy being absorbed by the cellulosictextile. On the other hand, accelerated electrons, which possess mass,are slowed down as a result of multiple collisions with the atoms of thecellulosic material or with atoms of the resin precondensate thusforming secondary electrons which-themselves collide with other atoms.At each collision of electrons energy is transferred and a relativelygreat part of the energy of the accelerated electrons is absorbed by thecellulosic textile and the condensable or resin-forming substancethereon. It has now been found that accelerated electrons of a very highparticle energy, that is above about 1 mev., transfer so much energyduring their passage through the cellulosic material that numerousscissions of the chain of the cellulosic molecule occur with resultingdecomposition and destruction of the textile. If, in accordance with thepresent invention, accelerated electrons of low particle energy areirradiated into the cellulosic material there is a much smaller transferof energy so that cellulose chain scission is very greatly reduced oreliminated, but the transferred energy is sufficient, perhaps beingdifferent in kind, to provide activation energy for the cellulose orresin precondensate to effect ionization and condensation.

Furthermore, in accordance with the present invention it has beenestablished that decomposition of the cellulose at a certain irradiatedtotal dose, e.g., l0 rad, is very substantially lower where acceleratedelectrons having a low particle energy, i.e., below 1 mev., are used ascompared with electrons of a particle energy above 1 mev. Where, inaccordance with the present invention, accelerated electrons of aparticle energy of between about 0.05 and 0.6 mev. are employed, thetotal dose to which the cellulosic textile is exposed can be maintainedat a sufficiently low value so that no decomposition of the celluloseworth mentioning takes place.

Accelerated electrons employed in accordance with the preesnt processmay be produced by the conventional electron accelerators, such as thecascade, Van de Graaf or linear types. Radioactive substances such as Sremitting beta radiation of a particle energy of 0.6 mev.,

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finishing of textiles of all kinds, as noted earlier, but isparticularly useful in the treatment of sheet materials or fabrics. Itis intended primarily for the crease-proof finishing and the impartingof dimensional stability to woven or knit cotton or rayon, or mixedcotton and rayon fabrics, and offers the further very significantadvantage in that the tearing and abrasive strength of the starting orunfinished fabric is very substantially increased. The finished fabricsexhibit a pleasant soft hand.

In accordance with the present method it is also possible to impart to afabric permanent embossing effects, such as gotfering, ribbing,schreinering, or moire effects, as well as calendaring effects with orWithout friction. The method is also effective in the treatment ofcellulosic textile yarns, filaments or threads. Excellent results areachieved in fabrics such as voiles and marquisettes fashioned of highlytwisted yarns, which fabrics normally exhibit a strong tendency toshrink.

Moreover, fine fabrics of cotton or regenerated cellulose which havebeen stiffened or transparentized by treatment with concentratedsulfuric acid, cuprammonium solution or sodium zincate cellulosesolution are very significantly improved by the present process, Withoutany decrease in fiber strength.

The method of the present invention will be further apparent from thefollowing typical examples, which illustrate practical applications ofthe method and describe certain characteristics of the novel finishedtextile products.

Example I A cotton imitation poplin was singed, desized and bleached andthereupon impregnated with a solution C011- W MIN/ 1 M 11492 My party anEttlllllft I H l H ill/lit it t. I l" i i and abrasive strength for thestarting unfinished cotton poplin fabric and for fabric Sections A, Band C.

- It will be noted that simply impregnating the fabric withdimethy-lolethyleneurea and drying at 60'70 C. appreciably increased thecrease angle, but at the expense of lowered tearing and abrasivestrengths. Irradiation with 2 mev. particles effected some improvementin the abrasive strength and also in the warp tearing strength, butappreciably reduced the warp crease angle. On the other hand, Section Cwhich was irradiated in accord ance with the method of the presentinvention employing low energy beta particles exhibited outstandinglysuperior crease angle, tearing strength and abrasive strength, as wellas an improved hand as compared with Section B.

Example III Crease angle Tearing strength Abrasive in degrees in g.strength in number of rotations Warp Fill Warp Fill Starting material 8200 195 3. 220 Irradiated 100 110 750 740 6. 140

Example IV A spun rayon gabardine fabric, pretreated in the usualmanner, was impregnated with a solution of dimethylolethyleneurea, asdescribed in Example I, and dried at 60-70 C. Thereupon it wasirradiated with accelerated electrons of a particle energy of 0.12 mev.to a total dose of 10 rad. The thus treated fabric exhibited excellentabrasive strength and crease resistance and unimpaired tearing strength.

Example V A cotton imitation poplin fabric was impregnated with anaqueous solution containing per liter 100 g. melamineformaldehydeprecondensate and 15 g. triethanolamine glycolate catalyst, squeezed outand dried at 60 C. Thereupon the fabric was irradiated with acceleratedelectrons of a particle energy of 0.1 mev. to a total dose of rad. Afterirradiation the fabric was washed with a soap soda solution at about 60C., dried and rinsed with cold water. The thus treated fabric had thefollowing properties:

Crease angle Tearing strength Abrasive in degrees in g. strength innumber of rotations Warp Fill Warp Fill Starting material 47 59 880 88015. 400 Irradiated 110 105 1, 030 1, 030 20. 810

6 Example VI The cotton imitation poplin fabric of Example V wasimpregnated with an aqueous solution containing per liter 102 g. of adiepoxide resin of the formula:

R=1 to 5 CH -groups and 6 g. zinc fluoroborate catalyst. It was thensqueezed out and dried at 60 C., washed, dried and rinsed as descrebedin Example V. Thereupon it was irradiated with accelerated electrons ofa particle energy of about 0.1 mev. to a total dose of 2 10 rad. Thethus treated fabric exhibited the following properties:

The cotton imitation poplin fabric of Example V was impregnated with anaqueous solution containing per liter g. of a glycol polyacetal, thepolymeric condensation product of diethyleneglycol and formaldehyde ofthe following general formula:

where X and Y are either H or CH OH, as described in US. Patent No.2,786,081, and 40 g. MgCl .6H O as catalyst. The fabric was thensqueezed out, dried at 60 C. and washed, dried and rinsed as describedin Example V. It was thereupon irradiated with accelerated electrons ofa particle energy of about 0.1 mev. to a total dose of 5 x 10 rad. Thethus treated fabric exhibited the following properties:

Crease angle Tearing strength Abrasive in degrees in g. strength innumber of rotations Warp Fill Warp Fill Starting Material 47 59 880 88015.400 Irradiated 110 105 1, 890 1, 690 26. 930

I claim:

1. A method of finishing a cellulosic textile of the group consisting ofcotton, rayon and mixtures thereof, which comprises impregnating thetextile with a crease-resistance imparting condensable resin-formingsubstance disposed in a fluid carrier, and subsequently subjecting theimpregnated textile to beta radiation of a particle energy between about0.05 and 1 mev. to a total radiation dose between about 10 and 2 10 radto condense the condensable substance on the textile and substantiallyimprove the abrasion and tensile strengths of the starting textile.

2. A crease resistant cellulosic textile finished by the process ofclaim 1.

3. A method as set forth in claim 1 wherein the beta radiation is of aparticle energy between about 0.05 and 0.6 mev.

4. A method as set forth in claim 1 wherein the fluid carrier is water.

5. A method as set forth in claim 1 wherein the impregnated textile isirradiated in wet condition.

6. A method as set forth in claim 1 wherein the impregnated textile isdried below about 100 C. before it is irradiated.

7. A method of finishing a fine cellulosic textile fabric of the groupconsisting of cotton, rayon and mixtures thereof, which comprisesimpregnating the textile with a crease-resistance imparting condensableresin-forming substance dispersed in a fluid carrier, and subsequentlysubjecting the impregnated textile to beta radiation of a particleenergy between about 0.05 and 0.6 rnev. to a total radiation dosebetween about 10 and 10 rads to condense the coudensable substance onthe textile and substantially improve the abrasion and tensile strengthsof the starting textile.

8. A fine cellulosic textile fabric finished by the process of claim 7.

References Cited by the Examiner UNITED STATES PATENTS 2,940,869 6/60Graham.

8 2,998,329 8/61 Sovish et al. 3,101,276 8/63 Hendricks 2.. 117-56FOREIGN PATENTS 758,735 10/56 Great Britain. 845,690 8/60 Great Britain.

OTHER REFERENCES Blouin: Textile Research Journal, vol. 28, 198204(1958).

Gilfillan: Textile Research Journal, vol. 25, 773-777 (1955).

Pan: Textile Research Journal, vol. 29, 415-421 (1959).

NORMAN G. TORCHIN, Primary Examiner.

MORRIS O. WOLK, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,206,273 September l4, 1965 Fritz Munzel hat error appears in the abovenumbered pat- It is hereby certified t etters Patent should read as entrequiring correction and that the said L corrected below.

lines 11 and 12, for "descrebed" read Column 6,

lines 32 to 35, the formula should appear as described shown belowinstead of as in the patent:

Signed and sealed this 3rd day of May 1966.

(SEAL) Attest:

EDWARD J. BRENNER ERNEST w. SWIDER \ttesting Officer Commissioner ofPatents

1. A METHOD OF FINISHING A CELLULOSIC TEXTILE OF THE GROUP CONSISTING OFCOTTON, RAYON AND MIXTURES THEREOF, WHICH COMPRISES IMPREGNATING THETEXTILE WITH A CREASE-RESISTANCE IMPAIRING CONDENSABLE RESIN-FORMINGSUBSTANCE DISPOSED IN A FLUID CARRIER, AND SUBSEQUENTLY SUBJECTING THEIMPREGNATED TEXTILE TO BETA RADIATION OF A PARTICLE ENERGY BETWEEN ABOUT0.05 AND 1 MEV. TO A TOTAL RADIATION DOSE BETWEEN ABOUT 10**4 AND2X10**6 RAD TO CONDENSE THE CONDENSABLE SUBSTANCE ON THE TEXTILE ANDSUBSTANTIALLY IMPROVE THE ABRASION AND TENSILE STRENGTHS OF THE STARTINGTEXTILE.